Track sledding machine

ABSTRACT

The invention relates to a machine for use in track sledding operations. Machine ( 1 ) comprises a wagon ( 2 ) having adjustably carried therebeneath a multibladed plough ( 3 ). A rail clamp assembly ( 4 ) is included for suspending the track above the plough during the sledding operations.

TECHNICAL FIELD

[0001] This invention relates to equipment for the maintenance of arailway. More particularly, the invention concerns machinery forremoving ballast from a railway.

BACKGROUND ART

[0002] Railways generally consist of a track supported by a bed ofcrushed rock or gravel, this bed being referred to as “ballast” in theart. Most tracks comprise a pair of rails fixed to lateral members knownas “sleepers” (or in some countries, “cross-ties”). Sleepers are formedfrom steel, timber or concrete.

[0003] There is a need as part of normal railway maintenance for theremoval of track ballast. This is usually brought about by the ballastbecoming fouled with soil or the like, or through there being excessiveballast present as a result of past maintenance. Ballast foulingprevents escape of water that can inundate the railway during heavy rainor flooding, while excessive ballast can lead to instability of therailway.

[0004] Ballast removal requires lifting of the track so that the ballastbetween and underneath the sleepers can be accessed. Normally, ballastremoval is necessary over many kilometres of railway. The process musttherefore be done mechanically as manual removal would be tooinefficient due to the amount of labour that would be required torapidly carry out the process to minimise track closure time.

[0005] Apparatus for removal of ballast is known in the art. One suchapparatus is a sled consisting of a plough that is V-shaped in plan andis mounted into a frame over which the track is passed as the sled isdrawn therebeneath. Skids are included in the frame to allow passage ofthe track over the sled which sled is pulled by steel cables connectedbetween the sled frame and a locomotive. Ballast removal using thisapparatus is referred to a “track sledding”.

[0006] There are a number of disadvantages in using the sled describedin the preceding paragraph for ballast removal. First, the cables bywhich the sled is pulled can break creating a potentially serious safetyhazard. Second, track components, particularly sleepers, can be damagedas the track slides over the sled. Third, there is insufficient controlover the sled during the sledding operation. Consequently, the remainingballast bed may have a poor surface and the resulting track alignmentpoor necessitating substantial additional resurfacing.

[0007] Other apparatus for removal of ballast utilises endless chains tocut the ballast out from the track. Apparatus of this type leaves thetrack with good alignment and surface. However, the apparatus has a highcapital cost of manufacture and is slow yet expensive to operate. Suchapparatus is known in the art as ballast undercutting machinery.

[0008] Because of the disadvantages of ballast undercutting machinery,track sledding apparatus is the apparatus of choice for ballast removal.There is nevertheless a need for track sledding apparatus that overcomesthe disadvantages of the apparatus described above. Specifically, thereis a need for a track sledding machine that meets the followingrequirements:

[0009] 1. the plough or any equivalent component is sufficientlycontrolled so that the surface of the remaining ballast or formationafter the sledding operation is close to the original surface or to adesired surface with respect to top and cant without the need forsubstantial resurfacing thereby providing a railway that is suitable forthe immediate passage of trains;

[0010] 2. the track alignment can be sufficiently controlled duringballast removal to minimise resurfacing alignment corrections so thatthe railway is again suitable for the immediate passage of trains,

[0011] 3. damage to track is eliminated or at least minimised; and

[0012] 4. it can be moved at a speed that permits efficient removal ofballast without compromising operator safety.

SUMMARY OF THE INVENTION

[0013] The object of the invention is to provide a track sleddingmachine that meets the requirements set out above.

[0014] In a broad format, the invention provides a track sleddingmachine comprising:

[0015] a railway wagon having adjustably carried therebeneath a ploughcomprising at least on plough blade; and

[0016] rail clamps for suspending said track above said plough to allowploughing of ballast with movement of said wagon.

[0017] The principle of the track sledding machine described in theprevious paragraph is that a plough is part of a machine of sufficientmass to provide for control of the plough during ballast removal. Thisresults in a consistency of the surface of the remaining ballast bed orformation. Furthermore, the use of rail clamps to support the trackclear of the plough as the plough passes thereunder reduces toessentially nil the instances of damage to track components. As themachine in its preferred embodiment is designed to be direct coupled toa standard locomotive, the major safety risk of at least the sleddingapparatus described above is eliminated.

[0018] To effect efficient operation of the plough in giving a ballastbed or formation surface that has close to the desired surface, themachine typically has a minimum weight of 60 or 70 tonnes depending onallowable axle loads for the track on which it is to operate. Thisensures that the plough is held at a constant level by the mass of themachine and is not displaced when a more firmly packed region of ballastor an obstacle within the ballast is encountered. The use of rail clampsfor elevating the track further enhances the stability of the machine inoperation—up to 30 tonne lift can be applied to the track in somecircumstances.

[0019] The wagon, or machine main frame, of the track sledding machineof the invention can be of any configuration. Advantageously, the wagoncomprises a horizontal frame to which bogies including brakes aremounted at each end thereof and has vertically extending framework towhich machine components and equipment of operating components can beattached.

[0020] The multibladed plough typically comprises a plurality of bladesthat are V-shaped in plan. The machine proceeds with the points of veesforemost during ploughing so that ballast is largely displaced to thesides of the track for subsequent removal if necessary. In instanceswhere displacement of ballast to only one side of the track is desired,the plough can be configured to include a plurality of blades that arestraight in plan but are angled across the machine. Displacement is thento the side of the machine at the trailing ends of the blades. Ploughscan also comprise a combination of V-shaped and straight blades toachieve the same end result of displacement of ballast to one side ofthe railway. Ploughs can be configured so that the angle of blades canbe varied. The angle of the “V” typically ranges between 60 to 120°.Straight blades can advantageously be varied through a range of 10 to60° to the plough centre-line.

[0021] Ploughs can have from one to twenty blades but typically havefrom four to eight blades. With a plough comprising V-shaped in planblades, a minimum of four blades is preferred although six blades arealso efficacious with straight blades.

[0022] The plough blades typically have a width of 100 to 300 mm. Thisallows cutting to a minimum of about 100 mm with there being sufficientheadroom between the chassis of the wagon and the elevated plough, andfor the track to be lifted within rail stress considerations.

[0023] Machines according to the invention can include blades forpre-cutting ballast. These blades are mounted, typically as pairs, aheadof the plough with the blades comprising a pair on opposite sides of themachine. In a machine based on a wagon of 20 m, there is sufficientspace ahead of a centrally positioned plough for from one to sixpre-cutter blades or blade pairs although machines can have from one toten or more pre-cutter blades or blade pairs. The pre-cutter bladesserve to remove ballast from the edges of the ballast bed to under theends of the sleepers. Where more than one pair of pre-cutter blades isfitted, the blades are configured so that a following blade undercuts asleeper more than the preceding blade. In such a configuration, thefirst pre-cutter blade removes the shoulder ballast close to the finaldesired depth of cut and an initial portion of ballast from under andbetween the sleeper ends. Lifting of the track above the pre-cutterblades is not required for ballast removal with the pre-cutter blades asthe track is still supported by the ballast that is as yet uncut. Thepre-cutter blades thus serve to reduce the amount of ballast that has tobe removed by the plough thereby allowing a greater depth of cut withthe plough.

[0024] In circumstances where the upper layer of ballast is unfouled,the plough can be set to return some of the upper layer to beneath thetrack by flow over the upper edges of the plough blades. That is, allballast is not necessarily displaced to the side or sides of the track.

[0025] In some instances it is desirable to selectively remove ballastfrom the upper, lower or middle section of the ballast bed. To achievethis end, the space between the blades can be covered with sheetmaterial, typically level with the top of the blades, so that ballastcannot enter the plough from above. Under this condition, the upperballast will slide over the top of the plough and be returned to thetrack whilst the ballast stratum in front of the plough or presented toeach individual blade is removed when the plough blades are drawntherethrough. Using such a covered, or “sheeted in”, plough, the lowerstratum of the ballast bed, for example, can be selectively removed.When pre-cutter blades are included in a machine, any spacestherebetween are also advantageously covered at otherwise they mayremove the stratum of ballast that is above the plough blades.

[0026] As an alternative to the full covering of the plough with sheetmaterial as described in the previous paragraph, the covering can be amesh or grating which has apertures of a sufficient size to allowunwanted smaller rock and fines to enter the plough and be dischargedwhilst the larger reusable ballast particles are passed over the ploughand returned to the track. In other embodiments of the invention, theplough can have spaces between blades alternately covered with sheetingand grating material.

[0027] In yet another embodiment, the leading blade of a covered ploughcan be replaced with a ramp which can lift essentially all of theballast over the plough.

[0028] The plough of machines according to the invention can haveassociated therewith a vibrator to enhance ballast flow over the ploughand separation of ballast.

[0029] The plough comprises a frame or at least two interconnected railsto which the blades are fixed. Blades typically have a concave leadingface and are fabricated from hardened steel. Ploughs can also includelongitudinally-extending skids on the upper edges of blades or on theplough frame to minimise damage to track in the event of a rail clampfailure or in the event of a sleeper falling from the track.

[0030] The adjustable carriage of the plough beneath the wagon istypically via arms of variable length fixed to at least the rear cornersof the plough with the upper ends of these arms fixed to the wagonframework. The machine also can include at least one drawbar extendingfrom the wagon to the leading edge of the plough. The plough ispreferably attached to the arms and any drawbar by shear pins designedto allow disengaging of the plough in the event of severe overload suchas encountering an obstruction in the ballast. Furthermore, the ploughcan include an offset ripper or scarifier tyne forward of the firstplough blade to feed any buried obstruction, such as a sleeper, to aside of the centreline of the machine and out of the way of the ploughduring ballast removal.

[0031] As the arms connected to at least the rear corners of the ploughare of variable lengths the longitudinal and lateral tilt of the ploughcan be adjusted. Longitudinal tilting of the plough allows the depth ofcut to be varied. Typically, the depth of cut is varied from of theorder of 100 mm below the bottom of the sleepers (when in situ on theballast) to up to about 400 mm below the bottom of the sleepers. Thisallows for merely the reduction of the amount of ballast in the railwayor essentially the entire removal of the ballast. The latter would applyin the instance of fouled ballast and removal would be followed byreplacement with fresh ballast. When longitudinally tilted, the highestblade is usually at the leading edge of the plough.

[0032] Lateral tilting of the plough allows the cant of the remainingballast bed or formation to be adjusted. Such tilting of the plough canbe by up to any angle with respect to the horizontal allowed by normalmachine and track geometry. To aid cant control, the suspension of thewagon lead bogie is locked out. This enables the machine frame(including plough and rail clamps) to follow closely the cant at thelead bogie thus minimising control inputs when curves and the like areencountered.

[0033] It will be appreciated by those of skill in the art that themaximum depth of cut of the plough is limited the plough capacity and byallowable rail stress during the ballast removal operation and themachine wheelbase. The maximum of 400 mm given above is achievable witha wagon having a 17 m wheelbase based on rail stress considerations.However, a greater maximum cut is achievable using a wagon with awheelbase of greater than 17 m.

[0034] The rail clamps used for suspending the track above the ploughcan be any rail clamp known to those of skill in the art. Typically, onepair of clamps are employed; although two pairs of clamps areadvantageous on longer wheelbases, one pair leading the plough and onepair trailing the plough with the clamps of a pair acting on oppositerails. Clamps advantageously include a mechanism that allows overridingof obstacles such as fishplates and weld flashing at rail junctions. Apreferred rail clamp is the roller rail clamp described in theapplicant's co-pending application entitled “Roller Rail Clamp”.

[0035] Continuously variable machine components, such as the variablelength arms associated with the plough, can be powered in any suitableway. A preferred power is hydraulic power and to facilitate this ahydraulic pump can be included in the machine with an appropriatehydraulic circuit. The machine typically also includes controls at anoperator station for adjusting machine components.

[0036] For maximum flexibility of the machine, the wagon isadvantageously configured so that it can be operated in eitherdirection. To do this, however, duplicate plough mountings must beprovided so that the plough can be reversed for operation in theopposite direction to that in which the machine was previously operated.

[0037] Prior to a ballast removal operation, the plough is disconnectedfrom the machine and installed under the track at the beginning of thesection of railway where ballast is to be removed. Installation of theplough of course requires lifting of the track with a crane or any othersuitable equipment. It will be appreciated that some excavation ofballast may be required to position the plough under the track. Themachine is then brought along the track over the plough and the ploughand rail clamps connected thereto. The ballast removal operation canthen be initiated. As an alternative to a crane or other equipment, therail clamps of the sledding machine can be used for lifting the trackfor plough installation. This eliminates a need for additionalequipment.

[0038] Following ballast removal, the plough is removed by a reversal ofthe installation procedure. If it is necessary to free the track fornormal railway traffic prior to completion of ballast removal from thesubject section of railway, the plough can be disconnected from thewagon and left in track for passage of such traffic thereover withappropriate reduction of speed.

[0039] There can be many other variations in the track sledding machineof the invention. Machines can have more than one plough per wagon. Thatis, the machine components set out above can be duplicated on a wagon toprovide tandem ploughs. Multiple ploughs can in fact be installedbeneath a single wagon. Alternatively, multiple machines comprising asingle plough per wagon can be used in a series operation. The multipleploughs associated with one wagon or with a series of wagons do notnecessarily have to be identical. The multiple ploughs can be anycombination of open ploughs and the covered ploughs described above.

[0040] To allow fitting of additional ploughs to a wagon, the wagon canhave an extendible main frame and/or a variable wheelbase.

[0041] As indicated above, in a preferred embodiment, the machine isdesigned to be coupled to a standard locomotive by which it can bepushed or pulled. However, the wagon comprising the machine can beself-propelled with an appropriate engine and drive train fittedthereto.

[0042] A sledding operation using a machine according to the inventioncan be in combination with activities such as ballast pick-up, cleaningand return. Other applications of the machine will be readilyrecognisable to one of skill in the art of track maintenance.

[0043] Having broadly described the invention, a machine will now beexemplified with reference to the accompanying drawings which will nowbe briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044]FIG. 1 is a partially schematic elevational view of a tracksledding machine according to the invention.

[0045]FIG. 2 is a plan view of the machine shown in FIG. 1.

[0046]FIG. 3 is a view in plan of the plough of the FIGS. 1 and 2machine.

[0047]FIG. 4 is an elevational view of the plough shown in FIG. 3.

[0048]FIG. 5 is an end elevation of a plough blade.

[0049] In the figures, the same item number is used for a featureincluded in more than one drawing. A particular drawing is notnecessarily to the same scale as other drawings.

BEST MODE AND OTHER MODES OF CARRYING OUT THE INVENTION

[0050] In FIGS. 1 and 2 there is shown track sledding machine 1comprising a wagon 2, plough assembly 3 and a rail clamp assembly 4. Thefigures are partially schematic and components have been omitted thatare not necessary to an understanding of how the machine functions.

[0051] Wagon 2 includes a horizontal frame 5 and a truss frame 6thereon. It has a length of 20 m. The wagon rolls on bogies 7 and 8, andhas standard buffers and couplings at each end thereof. The wagonfurther includes an engine module 9 for powering a hydraulic system (notshown in the figures) used for operating machine components, and acontrol console 10.

[0052] Plough assembly 3 is held below wagon 2 by carrier arms, one ateach corner of the assembly. The arms proximal the viewer in FIG. 1 areitems 11 and 12. Each carrier arm comprises an hydraulic ram and avernier pin adjustable slide. Alternatively, a carrier arm can comprisean hydraulic ram alone. Machine 1 also includes two drawbars, 13 and 14,extending from ends of a lateral member 15 fixed to horizontal frame 5of wagon 2 to the plough assembly (3). The plough assembly will bedescribed in greater detail below.

[0053] Rail clamp assembly 4 comprises a pair of clamps for each rail,one pair being indicated as items 16 and 17, which pairs of clamps arepivotally linked to wagon frame 5 by an arm and sub-assembly 18 (seeFIG. 1). A pair of hydraulic rams effects the lifting of track 19, onefor each rail, coupled between wagon frame 6 and sub-assembly 18. Theram closest the viewer in FIG. 1 is item 20.

[0054] The plough assembly 3 is shown in greater detail in FIGS. 3 and4. As can be seen from FIG. 3, plough assembly 3 comprises a number ofblades, one of which is indicated at 21. The blades can be seen to beV-shaped in plan and consist of two sub-blades 22 and 23. The assemblyincludes pre-blades. The pre-blades on one side of the plough are items24 and 25.

[0055] Plough assembly 3 is held together by side arms 26 and 27, and acentre spine 28. A transverse brace 29 links the side arms and centrespine. Leading blade 21 includes braces 30 and 31 extending from nearthe extremities of the sub-blades to centre spine 28. Plates areprovided with holes therethrough for attachment of the drawbars andcarrier arms. For example, plates 32 and 33 at leading end of side arm26 provide a point of attachment for drawbar 13 (see FIGS. 1 and 2).Plough assembly 3 is attached to the drawbars and carrier arms usingshear pins.

[0056]FIG. 5 is an end view of a blade which is in itself an assemblycomprising a curved blade 34 per se fixed via a plurality of webs, oneof which is item 35, to an elongate box section member 36. Web 35 andbox section member 36 are also indicated in FIG. 3.

[0057] The track sledding machine exemplified above is suited foroperation on track having rail sizes in the range of 41 to 60 kg/m. Theuse of the machine on such track for the reduction of ballast isillustrated in FIG. 1. After installation of plough assembly 3 Undertrack 19, wagon 2 is positioned thereover and the drawbars (13 and 14)and carrier arms (11 and 12) connected to the plough. The tilt of theplough is adjusted as required for the desired depth and cant-it can beseen in the figure that the trailing end of the plough (movement ofmachine 1 is to the left as viewed in FIG. 1) is lower than the leadingedge. It can also be appreciated from FIG. 1 that rail clamp assembly 4holds the track between the wagon bogies clear of the plough.

[0058] Movement of the machine results in the plough displacing ballastto the sides of plough assembly 3—see arrows in the plan view of FIG. 2.As a consequence, the track is lowered due to the reduction of theamount of ballast: compare the level of the track to the left of ploughassembly 3 in FIG. 1 to the level of the track to the right of theplough. If desired, the plough can be set so as to pass the top layer ofclean ballast over the tops of the plough blades to be deposited beyondthe plough under the trailing section 37 of track 19. This serves toeconomise on the ballast required for reinstatement of the track.

[0059] Machine 1, which has a total operational weight of 60 to 70tonne, is towed by a 90 or 120 tonne locomotive. Tandem locomotives canalso be used. With such locomotives, the sledding operation can beperformed at 5 to 20 km per hour depending on the condition of thetrack, with 5 to 10 km/hr being a typical speed. It will be appreciatedfrom FIG. 1 that the length of the wagon allows suspension of the trackabove the plough yet the weight of the machine as a whole gives fullcontrol over the plough so that ballast is efficiently removed.Furthermore, the machine geometry allows track to be lowered to withinabout 30 mm of the original track centreline. Additional, the rail clampassembly can be manually or automatically controlled to effect trackoffset with respect to an initial datum.

[0060] It will be appreciated that many changes can be made to the tracksledding machine and use thereof as exemplified above without departingfrom the broad ambit and scope of the invention

[0061] The term “comprise”, or variants thereof such as “comprising” or“comprised”, is used herein to denote the inclusion of a stated integeror integers, unless is the context of usage an exclusive interpretationof the term is required.

1. A track sledding machine comprising: a railway wagon havingadjustably carried therebeneath a plough comprising at least one ploughblade; and rail clamps for suspending said track above said plough toallow continuous ploughing of ballast with movement of said wagon. 2.The machine according to claim 1, wherein said wagon is adapted forconnection to a locomotive and comprises a horizontal frame with spacedapart bogies having a vertical frame thereon for mounting of machinecomponents.
 3. The machine according to claim 1, wherein said wagon isof variable length.
 4. The machine according to claim 1, wherein saidwagon is self-propelled.
 5. The machine according to claim 1, whereinsaid plough comprises a plurality of blades that are V-shaped in planwith the points of vees foremost in use.
 6. The machine according toclaim 5, wherein the angle of the vee of said blades ranges from 60 to120°.
 7. The machine according to claim 1, wherein said plough comprisesa plurality of blades that are straight in plan but angled relative tothe centre-line of said wagon.
 8. The machine according to claim 6,wherein the angle of said blades can be varied through a range of 10 to60° from the plough centre-line.
 9. The machine according to claim 1,wherein said plough comprises from one to twenty blades.
 10. The machineaccording to claim 9, wherein said plough comprises four blades.
 11. Themachine according to claim 1, wherein said machine includes at least oneblade ahead of said plough for pre-cutting ballast.
 12. The machineaccording to claim 11, wherein said pre-cutter blades are in pairs withthe blades of a said pair on opposite sides of said machine.
 13. Themachine according to claim 11, comprising from one to ten pre-cutterblades or pairs of pre-cutter blades.
 14. The machine according to claim12, comprising at least two pairs of pre-cutter blades and wherein saidpairs are configured so that a following blade cuts deeper than thepreceding blade.
 15. The machine according to claim 1, wherein saidplough blades have a concave face.
 16. The machine according to claim 1,wherein said plough comprises a frame on at least two interconnectedrails to which said blades are fixed.
 17. The machine according to claim1, wherein longitudinally-extending skids are provided on the upperedges of blades or on a frame to which said blades are fixed.
 18. Themachine according to claim 1, wherein said adjustable carriage of saidplough is via arms of variable length fixed to at least the rear cornersof said plough with upper ends of said arms fixed to wagon framework.19. The machine according to claim 18, comprising arms of adjustablelength at each corner of said plough.
 20. The machine according to claim19, wherein said adjustable arms are hydraulic rams.
 21. The machineaccording to claim 19, wherein said arms are attached to said plough vialongitudinal slides.
 22. The machine according to claim 1, wherein atleast one drawbar is provided that extends from the leading edge of saidplough to said wagon.
 23. The machine according to claim 22, whereinsaid at least one drawbar is attached to said plough via a shear pin.24. The machine according to claim 1, wherein an offset ripper orscarifier tyne is included in said plough forward of the leading ploughblade.
 25. The machine according to claim 1, wherein at least two pairsof rail clamps are provided, wherein one pair leads the plough and theanother pair trails said plough with clamps of a pair acting on oppositerails.
 26. The machine according to claim 25, wherein said rail clampsare roller rail clamps.
 27. The machine according to claim 1, whereinsaid plough comprises a plurality of blades and is covered.
 28. Themachine according to claim 27, wherein said covering comprises sheetmaterial or grating spanning spaces between said blades at the upperedges thereof.
 29. The machine according to claim 27, wherein saidcovering comprises a combination of sheet material or grating spanningspaces between said blades at the upper edges thereof.
 30. The machineaccording to claim 27, wherein said first blade is replaced with a rampto direct ballast over said plough.
 31. The machine according to claim1, wherein said plough has a mesh covering to allow fines and othersmaller ballast particles to fall into the plough and be dischargedwhilst larger ballast particles pass over the plough and are returned totrack.
 32. The machine according to claim 1 having a vibrator associatedwith said plough to enhance ballast flow over the plough and separationof ballast.
 33. The machine according to claim 1 comprising a pluralityof ploughs.